<template>
  <view
    class="main-content"
    @touchmove.stop.prevent=""
  >
    <!-- 签字canvas -->
    <canvas 
      id="mycanvas" 
      class="mycanvas" 
      canvas-id="mycanvas" 
      @touchstart="touchstart" 
      @touchmove="touchmove" 
      @touchend="touchend"
    />
    <!-- 旋转canvas -->
    <canvas
      id="rotatCanvas"
      class="mycanvas"
      :style="{ 'z-index': -1, width: `${screenWidth}px`, height: `${(screenWidth * screenWidth) / screenHeight}px` }"
      canvas-id="rotatCanvas"
    />
    <cover-view class="button-line">
      <cover-view
        class="save-button"
        @tap="finish"
      >
        保存
      </cover-view>
      <cover-view
        class="clear-button"
        @tap="clear"
      >
        清除
      </cover-view>
      <cover-view
        class="cancel-button"
        @tap="hide"
      >
        关闭
      </cover-view>
    </cover-view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        ctx: '', //绘图图像
        points: [], //路径点集合
        screenWidth: '',
        screenHeight: '',
      };
    },
    mounted(query) {
      this.createCanvas();
      uni.getSystemInfo({
        success: e => {
          this.screenWidth = e.screenWidth;
          this.screenHeight = e.screenHeight;
        }
      });
    },
    methods: {
      show() {
        this.clear();
      },
      hide() {
        this.$emit('close');
      },
      //创建并显示画布
      createCanvas() {
        this.showCanvas = true;
        this.ctx = uni.createCanvasContext('mycanvas', this); //创建绘图对象
        //设置画笔样式
        this.ctx.lineWidth = 12;
        this.ctx.strokeStyle = '#000000'
        this.ctx.lineCap = 'round';
        this.ctx.lineJoin = 'round';
      },
      //触摸开始，获取到起点
      touchstart(e) {
        let startX = e.changedTouches[0].x;
        let startY = e.changedTouches[0].y;
        let startPoint = {
          X: startX,
          Y: startY
        };
        this.points.push(startPoint);
        //每次触摸开始，开启新的路径
        this.ctx.beginPath();
      },
      //触摸移动，获取到路径点
      touchmove(e) {
        let moveX = e.changedTouches[0].x;
        let moveY = e.changedTouches[0].y;
        let movePoint = {
          X: moveX,
          Y: moveY
        };
        this.points.push(movePoint); //存点
        let len = this.points.length;
        if (len >= 2) {
          this.draw(); //绘制路径
        }
      },
      // 触摸结束，将未绘制的点清空防止对后续路径产生干扰
      touchend() {
        this.points = [];
      },
      /* ***********************************************
			#   绘制笔迹
			#	1.为保证笔迹实时显示，必须在移动的同时绘制笔迹
			#	2.为保证笔迹连续，每次从路径集合中区两个点作为起点（moveTo）和终点(lineTo)
			#	3.将上一次的终点作为下一次绘制的起点（即清除第一个点）
			************************************************ */
      draw() {
        let point1 = this.points[0];
        let point2 = this.points[1];
        this.points.shift();
        this.ctx.moveTo(point1.X, point1.Y);
        this.ctx.lineTo(point2.X, point2.Y);
        this.ctx.stroke();
        this.ctx.draw(true);
      },
      //清空画布
      clear() {
        this.ctx.clearRect(0, 0, this.screenWidth, this.screenHeight);
        this.ctx.draw(true);
      },
      //完成绘画并保存到本地
      finish() {
        // if (this.points.length == 0) {
        //   this.$x.notify.showToast('请签名')
        //   return
        // }
        uni.canvasToTempFilePath(
          {
            canvasId: 'mycanvas',
            success: res => {
              this.rotat(res.tempFilePath);
            },
            complete: com => {
              console.log('finish',com)
            }
          },this
        );
      },
      // 将图片旋转
      rotat(e) {
        let rotatCtx = uni.createCanvasContext('rotatCanvas', this); //创建绘图对象
        // 重新定位中心点
        rotatCtx.translate(0, (this.screenWidth * this.screenWidth) / this.screenHeight);
        // 将画布逆时针旋转90度
        rotatCtx.rotate((270 * Math.PI) / 180);
        // rotatCtx.rotate(Math.PI/2);
        // 将签字图片绘制进入Canvas
        rotatCtx.drawImage(e, 0, 0, (this.screenWidth * this.screenWidth) / this.screenHeight, this.screenWidth);
        // 保存后旋转后的结果
        rotatCtx.draw(true);
        setTimeout(() => {
          // 生成图片并回调
          uni.canvasToTempFilePath(
            {
              canvasId: 'rotatCanvas',
              success: result => {
                console.log('rotat canvasToTempFilePath success',result)
                // 压缩图片
                uni.compressImage({
                  src: result.tempFilePath,
                  quality: 70,
                  width: '200px',
                  height: 'auto',
                  success: compressRes => {
                    console.log('compressImage success',compressRes)
                    this.$emit('sign', compressRes.tempFilePath);
                  },
                  fail: error => {
                    console.log('compressImage fail',error)
                  },
                })
                // setTimeout(() => {
                //   this.hide();
                // }, 500);
              },
              complete: com => {
                console.log('rotat canvasToTempFilePath complete',com);
              },
              fail: error => {
                console.log('rotat canvasToTempFilePath fail',error);
              },
            },this
          );
        }, 500);
      }
    }
  };
</script>

<style lang="scss" scoped>
.main-content {
	width: 100vw;
	height: 100vh;
	// background-color: red;
	position: fixed;
	top: 0rpx;
	left: 0rpx;
	z-index: 9999;
}
.mycanvas {
	width: 100vw;
	height: 100vh;
	background-color: #efefef;
	position: fixed;
	left: 0rpx;
	top: 0rpx;
	z-index: 2;
}
.button-line {
	transform: rotate(90deg);
	position: fixed;
	bottom: 170rpx;
	left: -100rpx;
	width: 340rpx;
	height: 50rpx;
	display: flex;
	align-items: center;
  justify-content: center;
	// justify-content: space-between;
	z-index: 999;
}
.button-style {
	color: #ffffff;
	width: 100rpx;
	height: 60rpx;
	text-align: center;
	line-height: 60rpx;
	border-radius: 10rpx;
}
.save-button {
  margin-right: 10px;
	@extend .button-style;
	background-color: $uni-color-primary;
}
.clear-button {
  margin-right: 10px;
	@extend .button-style;
	background-color: $uni-color-error;
}
.cancel-button {
	@extend .button-style;
	background-color: #e10b2b;
}
</style>